DH_AES_HMAC.java

import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.Cipher;
import javax.crypto.KeyAgreement;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.interfaces.DHPrivateKey;
import javax.crypto.interfaces.DHPublicKey;
import javax.crypto.spec.DHParameterSpec;
import javax.crypto.spec.SecretKeySpec;


/**
 * DH算法协商共享密钥
 * 对称加密算法AES用作数据加解密
 * HMAC算法用作消息完整性和可靠性检验
 * @author 20175415-何万有
 * */
public class DH_AES_HMAC {
    // 非对称密钥算法
    public static final String KEY_ALGORITHM="DH"; 
    // 对称加密算法
    public static final String SECRET_ALGORITHM="AES";
    // 密钥长度
    private static final int KEY_SIZE=512;
    // 公钥
    private static final String PUBLIC_KEY="DHPublicKey";
    // 私钥
    private static final String PRIVATE_KEY="DHPrivateKey";
    // HMAC算法
    private static final String ALGORITHM_MAC = "HmacMD5";
    
    /**
     * 初始化甲方密钥
     * @return Map 甲方密钥的Map
     * */
    public static Map<String,Object> initKey() throws Exception{
        //实例化密钥生成器
        KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance(KEY_ALGORITHM);
        //初始化密钥生成器
        keyPairGenerator.initialize(KEY_SIZE);
        //生成密钥对
        KeyPair keyPair=keyPairGenerator.generateKeyPair();
        //甲方公钥
        DHPublicKey publicKey=(DHPublicKey) keyPair.getPublic();
        //甲方私钥
        DHPrivateKey privateKey=(DHPrivateKey) keyPair.getPrivate();
        //将密钥存储在map中
        Map<String,Object> keyMap=new HashMap<String,Object>();
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
        
    }
    
    /**
     * 初始化乙方密钥
     * @param key 甲方密钥
     * @return Map 乙方密钥的Map
     * */
    public static Map<String,Object> initKey(byte[] key) throws Exception{
        //解析甲方的公钥
        //转换公钥的材料
        X509EncodedKeySpec x509KeySpec=new X509EncodedKeySpec(key);
        //实例化密钥工厂
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);
        //产生公钥
        PublicKey pubKey=keyFactory.generatePublic(x509KeySpec);
        //由甲方的公钥构造乙方密钥
        DHParameterSpec dhParamSpec=((DHPublicKey)pubKey).getParams();
        //实例化密钥生成器
        KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance(keyFactory.getAlgorithm());
        //初始化密钥生成器
        keyPairGenerator.initialize(dhParamSpec);
        //产生密钥对
        KeyPair keyPair=keyPairGenerator.genKeyPair();
        //乙方公钥
        DHPublicKey publicKey=(DHPublicKey)keyPair.getPublic();
        //乙方私钥
        DHPrivateKey privateKey=(DHPrivateKey)keyPair.getPrivate();
        //将密钥存储在Map中
        Map<String,Object> keyMap=new HashMap<String,Object>();
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }
    
    /**
     * 加密
     * @param data 明文
     * @param key 密钥
     * @return byte[] 密文
     * */
    public static byte[] AESEncrypt(byte[] data,byte[] key) throws Exception{
        //生成本地密钥
        SecretKey secretKey=new SecretKeySpec(key,SECRET_ALGORITHM);
        //数据加密
        Cipher cipher=Cipher.getInstance(secretKey.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        return cipher.doFinal(data);
    }
    
    /**
     * 解密
     * @param data 密文
     * @param key 密钥
     * @return byte[] 明文
     * */
    public static byte[] AESDecrypt(byte[] data,byte[] key) throws Exception{
        //生成本地密钥
        SecretKey secretKey=new SecretKeySpec(key,SECRET_ALGORITHM);
        //数据解密
        Cipher cipher=Cipher.getInstance(secretKey.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        return cipher.doFinal(data);
    }
    
    /**
     * 构建密钥
     * @param publicKey 公钥
     * @param privateKey 私钥
     * @return byte[] 本地密钥
     * */
    public static byte[] getSecretKey(byte[] publicKey,byte[] privateKey) throws Exception{
        //实例化密钥工厂
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);
        //初始化公钥
        //密钥材料转换
        X509EncodedKeySpec x509KeySpec=new X509EncodedKeySpec(publicKey);
        //产生公钥
        PublicKey pubKey=keyFactory.generatePublic(x509KeySpec);
        //初始化私钥
        //密钥材料转换
        PKCS8EncodedKeySpec pkcs8KeySpec=new PKCS8EncodedKeySpec(privateKey);
        //产生私钥
        PrivateKey priKey=keyFactory.generatePrivate(pkcs8KeySpec);
        //实例化
        KeyAgreement keyAgree=KeyAgreement.getInstance(keyFactory.getAlgorithm());
        //初始化
        keyAgree.init(priKey);
        keyAgree.doPhase(pubKey, true);
        //生成本地密钥
        SecretKey secretKey=keyAgree.generateSecret(SECRET_ALGORITHM);
        return secretKey.getEncoded();
    }
    
    /**
     * 取得私钥
     * @param keyMap 密钥map
     * @return byte[] 私钥
     * */
    public static byte[] getPrivateKey(Map<String,Object> keyMap){
        Key key=(Key)keyMap.get(PRIVATE_KEY);
        return key.getEncoded();
    }
    
    /**
     * 取得公钥
     * @param keyMap 密钥map
     * @return byte[] 公钥
     * */
    public static byte[] getPublicKey(Map<String,Object> keyMap) throws Exception{
        Key key=(Key) keyMap.get(PUBLIC_KEY);
        return key.getEncoded();
    }
    
    /** 
     * @param key 密钥字符串 
     * @param algorithm 加密算法 
     * @return 返回密钥对象 
     */  
    private static Key toKey(byte[] key,String algorithm) {  
        SecretKey secretKey = new SecretKeySpec(key, algorithm);
        return secretKey;  
    }
    
    /** 
     * 使用HMAC加密 
     * @param data 要加密的数据 
     * @param key 密钥 
     * @return 返回加密后的信息 
     */  
    public static byte[] HMACEncode(byte[] data, byte[] key) {  
        Key k = toKey(key,ALGORITHM_MAC);
        try {  
            Mac mac = Mac.getInstance(k.getAlgorithm());  
            mac.init(k);  
            return mac.doFinal(data);  
        } catch (NoSuchAlgorithmException e) {  
            e.printStackTrace();  
        } catch (InvalidKeyException e) {  
            e.printStackTrace();  
        }  
        return null;  
    }
}